Golf ball compositions based on anionic polymers

ABSTRACT

The present invention provides golf balls having a cover, a core, and optionally one or more intermediate layers between the cover and the core, wherein at least one of the cover, the core and, if present, the intermediate layer or layers, includes an anionic polymer. The anionic polymer has at least one of a neutralizable hydroxyl or dealkylable ether group, at least a portion of which are neutralized or dealkylated by a metal ion to provide anionic moieties. The anionic polymer compositions of the present invention can be used to provide improved characteristics to golf balls made therefrom.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 09/219,348filed Dec. 23, 1998 now U.S. Pat. No. 6,221,960, the disclosure of whichis hereby incorporated herein by express reference thereto.

FIELD OF THE INVENTION

The present invention relates to golf balls and, in particular, topolymeric compositions useful in golf ball covers, cores, andintermediate layers between the cover and the core. The polymericcompositions include at least one anionic polymer which hasneutralizable hydroxyl and/or dealkylable ether groups, at least aportion of which are neutralized by a metal ion to provide anionicgroups attached to the polymer.

BACKGROUND OF THE INVENTION

Three-piece, wound-core golf balls with balata (trans-polyisoprene)covers are typically preferred by professional and low handicap amateurgolfers. These balls provide a combination of distance, high spin rate,and control that is not available with other types of golf balls.However, balata is easily damaged in normal play, and thus lacks thedurability required by the average golfer.

Two-piece golf balls, which are typically used by the average amateurgolfer, provide a combination of durability and maximum distance that isnot available with balata covered balls. These balls comprise a core,formed of a solid sphere which typically comprises a polybutadiene-basedcompound, encased in an ionomer cover, such as SURLYN®. Golf ball coverionomers are, typically, copolymers of an olefin and an unsaturatedcarboxylic acid in which at least a portion of the carboxylic acidgroups have been neutralized with a metal ion, typically sodium or zinc.These balls are extremely durable, have good shear resistance, and aredifficult to cut. However, this durability results from the hardness ofthe ionomer, which gives such balls a very hard “feel” when struck,which many golfers find inferior to the softer “feel” of a balatacovered ball. In addition, the hardness of the ionomer gives the balls alower spin rate, making these balls more difficult to control.

Many attempts have been made to produce a golf ball with the control andfeel of a wound balata ball, and the durability of an ionomer coveredtwo-piece ball. These attempts have focused largely on modifying theproperties of ionomer compositions by forming ionomer blends.

For example, U.S. Pat. Nos. 4,884,814, 5,120,791, 5,324,783, 5,415,937and 5,492,972 disclose ball compositions which are blends ofhigh-hardness ionomers and low-hardness ionomers. Other patents discloseblends of ionomers and nonionic polymers, such as U.S. Pat. Nos.5,397,840, 5,516,847, 5,703,166. These patents attempt to overcome theinherent immiscibility of ionomers and nonionic polymers by adding polarfunctionalities to the nonionic polymers (see, e.g., U.S. Pat. Nos.4,986,545 and 5,359,000), or by adding compatibilizers to provide orenhance the compatibility of the two polymer species (see, e.g., U.S.Pat. Nos. 5,155,157 and 5,321,089, and Japanese patent application6,192,512 (1994)). Still other patents disclose blends of normallyimmiscible or poorly miscible non-ionomer polymers with compatibilizers(see, e.g., U.S. Pat. No. 5,422,398).

U.S. Pat. No. 4,526,375 discloses golf balls having improved lowtemperature impact resistance including a cover composition having anionic polymer with at least two different metal ions in one molecule.

U.S. Pat. No. 5,692,974 discloses compositions using cationic polymershaving positively charged quaternary ammonium groups. The cationicgroups, preferably present in cationic polyurethane polymers, impartimproved characteristics to golf ball covers formed therefrom.

Notwithstanding these efforts, there is no known prior art disclosure ofthe use of anionic polymers having anionic groups derived from other,non-carboxylic acid, neutralizable moieties, such as hydroxyl anddealkylable moieties, such as ether groups, to form golf balls. Suchanionic polymers would have desirable hydrogen bonding or dipoleinteractions as well as ionic interactions which can be utilized toimpart improved characteristics to golf ball cores, covers, andintermediate layers, such as improved durability and resiliency.

Thus, there has now been discovered surprisingly improved golfball-forming compositions comprising anionic polymers having anionicmoieties derived from neutralizable hydroxyl and/or dealkylable ethergroups, which, when used to form golf balls, produce balls whichunexpectedly remedy the deficiencies of the prior art materialsdiscussed above.

SUMMARY OF THE INVENTION

The present invention is directed to golf balls comprising a cover, acore, and optionally one or more intermediate layers disposed betweenthe cover and the core, wherein at least one of the cover, the core and,if present, the intermediate layer or layers, comprises an anionicpolymer having neutralizable hydroxyl and/or dealkylable ether groups,wherein the golf ball has a coefficient of restitution of greater thanabout 0.7 and a compression of at least about 50, the cover has athickness of at least about 0.03 inches and at least about 60 percentdimple coverage, and the anionic polymer has a flexural modulus fromabout 500 psi to 300,000 psi, a hardness of at least about 15 Shore A, aspecific gravity of at least about 0.7, a dynamic shear storage modulusof at least about 10⁴ dyn/cm², and a loss tangent of less than about 1at about 23° C. At least a portion of the neutralizable or dealkylablegroups are neutralized by a metal base to leave anionic moietiesattached to the polymer.

The anionic polymer comprises repeating units of formula (Ia):

wherein R₁, is OH, OC(O)R₅, O⁻M^(+V), (CH₂)_(n)R_(b),(CHR_(z))_(n)R_(b), or aryl, wherein n is at least 1, R₅ is a loweralkyl, M is a metal ion, V is an integer from 1 to 5, R_(b) is OH,OC(O)R₅, O⁻M^(+V), and R_(z), is a lower alkyl or aryl, R₂, R₃ and R₄are each independently selected from the group consisting of hydrogen,straight-chain or branched-chain lower alkyl, and substituted alkyl inwhich one or more hydrogen atoms is replaced by a substituent selectedfrom the group consisting of COOH, SO₃H, NH₂ or a lower alkylsubstituted or di-substituted amine, halogen, OH, SH, silicone, andlower alkyl ether.

In a preferred embodiment, the anionic polymer is a copolymer ofsubstituted or unsubstituted ethylene and substituted or unsubstitutedvinyl alcohol, acetate, p-hydroxy styrene, or p-methoxy styrene. Thus,in this embodiment, the anionic copolymer is a random, block, oralternating copolymer of units (Ia) and (Ib), where units (Ib) have theformula

wherein R₆, R₇, R₈ and R₉ are each independently selected from the groupas defined above for R₂. In a preferred embodiment, each of R₂, R₃, R₄,R₆, R₇, R₈ and R₉ is hydrogen. In another preferred embodiment, R₅ ismethyl.

In one embodiment, the units Ia are present in amounts from about 1 to99 weight percent and units Ib are present in amounts from about 99 to 1weight percent.

In a more preferred embodiment, the anionic polymer is a copolymer ofethylene and vinyl alcohol, vinyl acetate, i.e., R₁, is OH or OC(O)CH₃,p-hydroxy styrene, or p-methoxy styrene, and the remaining R groups arehydrogen.

In another embodiment, the anionic polymer is a copolymer or terpolymerof formula (II):

wherein:

R₁-R₉ are each independently selected from the groups defined above;

R₁₀-R₁₂ are each independently selected from the group as defined abovefor R₂; and

R₁₃ is OH or OC(O)R₁₄, where R₁₄ is a lower alkyl;

the remaining R groups are each independently selected from the groupconsisting of hydrogen, straight-chain or branched-chain lower alkyl,and substituted alkyl in which one or more hydrogen atoms is replaced bya substituent selected from the group consisting of COOH, SO₃H, NH₂ or alower alkyl substituted or di-substituted amine, halogen, OH, SH,silicone, lower alkyl ether, and lower alkyl ether;

x ranges from about 99 to 50 weight percent of the polymer, y rangesfrom about 1 to 50 weight percent of the polymer, and z ranges fromabout 0 to 50 weight percent of the polymer; and

wherein at least a portion of the neutralizable groups are neutralizedwith a metal ion.

The anionic polymers of the present invention can be mixed with one ormore additional ionic and non-ionic polymers, present in an amount ofabout 1 to 99 percent by weight, preferably about 5 to 80 percent, basedon the total weight of the anionic polymer and the additional polymer.Preferred additional polymers include polyvinyl alcohol or a copolymerof ethylene and vinyl alcohol, styrene-allyl alcohol, or ethylene-allylalcohol copolymer.

In a preferred embodiment, the anionic polymer has a flexural modulus offrom about 2,000 to 200,000 psi. In yet another embodiment, the metalion is an ion of an alkali metal, an alkaline earth metal, a transitionmetal, a Group III metal, or a Group IV metal. In a preferredembodiment, the alkali metal is lithium, sodium or potassium; thealkaline earth metal is magnesium; and the transition metal is titanium,zirconium, tungsten or zinc.

In one optional, but preferred, embodiment, the at least oneintermediate layer is disposed between the cover and the core. Inanother optional, but more preferred embodiment, said intermediate layeris formed of a composition which comprises an anionic polymer having atleast one of a neutralizable hydroxyl or dealkylable ether group, and atleast a portion of the neutralizable or dealkylable groups areneutralized with a metal ion.

In one embodiment, the core contains at least one solid, hollow, orfluid portion. In another embodiment, at least one of the intermediatelayers includes a tensioned elastomeric material. In yet anotherembodiment, at least a portion of at least one of the core, the at leastone intermediate layer, and the cover is foamed, comprises adensity-modifying filler, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a two-piece golf ball according tothe invention having a cover and a core.

FIG. 2 is a cross-section of a golf ball according to the inventionhaving an intermediate layer between a cover and a core.

FIG. 3 is a cross-section of a golf ball according to the inventionhaving more than one intermediate layer between a cover and a core.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the present invention relates to golf ball formingcompositions comprising an anionic polymer having anionic groups derivedfrom neutralization of hydroxyl and/or dealkylable ether groups, whereinthe polymer has a flexural modulus from about 500 psi to 300,000 psi, ahardness of at least about 15 Shore A, a specific gravity of at leastabout 0.7, a dynamic shear storage modulus of at least about 10⁴dyn/cm², and a loss tangent of less than about 1. The dynamic shearstorage is defined according to ASTM Standards D4092-90, D4065-94, andD5279-93. The anionic polymers useful in the present invention includeany homopolymer, copolymer or terpolymer having neutralizable hydroxyland/or dealkylable ether groups, and in which at least a portion of theneutralizable or dealkylable groups are neutralized or dealkylated witha metal ion.

As used herein “neutralizable” or “dealkylable” groups refer to ahydroxyl or ether group pendent from the polymer chain and capable ofbeing neutralized or dealkylated by a metal ion, preferably a metal ionbase. These neutralized polymers have improved properties critical togolf ball performance, such as resiliency, impact strength and toughnessand abrasion resistance. Suitable metal bases are ionic compoundscomprising a metal cation and a basic anion. Examples of such basesinclude hydroxides, carbonates, acetates, oxides, sulfides, and thelike.

The particular base to be used depends upon the nature of the hydroxylor ether compound to be neutralized or dealkylated, and is readilydetermined by one skilled in the art. Preferred anionic bases includehydroxides, carbonates, oxides and acetates.

The metal ion can be any metal ion which forms an ionic compound withthe anionic base. The metal is not particularly limited, and includesalkali metals, preferably lithium, sodium or potassium; alkaline earthmetals, preferably magnesium or calcium; transition metals, preferablytitanium, zirconium, or zinc; and Group III and IV metals. The metal ioncan have a +1 to +5 charge. Most preferably, the metal is lithium,sodium, potassium, zinc, magnesium, titanium, tungsten, or calcium, andthe base is hydroxide, carbonate or acetate.

The anionic polymers useful in the present invention include those whichcontain neutralizable hydroxyl and/or dealkylable ether groups.Exemplary polymers include ethylene vinyl alcohol copolymers, polyvinylalcohol, polyvinyl acetate, poly(p-hydroxymethylene styrene), andp-methoxy styrene, to name but a few. It will be apparent to one skilledin the art that many such polymers exist and thus can be used in thecompositions of the invention. Thus, in one embodiment, the anionicpolymer comprises repeating units of formula (Ia):

where R₁ is OH, OC(O)R₅,O⁻M^(+V), (CH₂)_(n)R_(b), (CHR_(z))_(n)R_(b), oraryl, wherein n is at least 1, R₅ is a lower alkyl, M is a metal ion, Vis an integer from 1 to 5, R_(b) is OH, OC(O)R₅, O⁻M^(+V), and R_(z) isa lower alkyl or aryl, and R₂, R₃ and R₄ are each independentlyhydrogen, straight-chain or branched-chain lower alkyl. R₂, R₃ and R₄may also be similarly substituted. Preferably n is from 1 to 12, morepreferably 1 to 4.

The term “substituted,” as used herein, means one or more hydrogen atomshas been replaced by a functional group. Functional groups include, butare not limited to, hydroxyl, amino, carboxyl, sulfonic, amide, ether,ether, phosphates, thiol, nitro, silane, and halogen, as well as manyothers which are quite familiar to those of ordinary skill in this art.

The terms “alkyl” or “lower alkyl,” as used herein, includes a group offrom about 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms.

In the anionic polymers useful in the present invention, at least aportion of the neutralizable or dealkylable groups of R₁ are neutralizedor dealkylated by a metal base to form the corresponding anionic moiety.The metal ion of the metal base remains associated with the anionicpolymer moiety, to form an O⁻M^(+V) group, where M^(+V) is a metalcation of charge V. The portion of the neutralizable or dealkylablegroups which are neutralized or dealkylated can be between about 1 to100 weight percent, preferably between about 5 to 50 weight percent.

Neutralization or dealkylation may be performed by melting the polymerfirst, then adding a metal ion in an extruder. The degree ofneutralization or dealkylation is controlled by varying the amount ofmetal ion added. Any method of neutralization or dealkylation availableto those of ordinary skill in the art may also be suitably employed.

In one embodiment, the anionic polymer is repeating units of fonnula(Ia), as described above. In a preferred embodiment, R₂, R₃, and R₄ arehydrogen, and R₁ is hydroxyl, i.e., the anionic polymer is a polyvinylalcohol homopolymer in which a portion of the hydroxyl groups have beenneutralized with a metal base. In another preferred embodiment, R₂, R₃,and R₄ are hydrogen, and R₁ is OC(O)R₅, and R₅ is methyl, i.e., theanionic polymer is a polyvinyl acetate homopolymer in which a portion ofthe methyl ether groups have been neutralized with a metal base.

The anionic polymer can also be a copolymer of two different repeatingunits of formula (Ia) having different substituents, or a terpolymer ofthree different repeating units of formula (Ia). In this embodiment, thepolymer can be a random copolymer, an alternating copolymer, or a blockcopolymer, where the term “copolymer” includes terpolymers.

In another embodiment, the anionic polymer is a copolymer of units (Ia)and (Ib), as described above, where units (Ib) have the formula:

wherein R₆, R₇, R₈ and R₉ are each independently selected from the groupdefined above for R₂. Units of formula (Ia) can comprise from about 1 to99 percent weight percent of the polymer, preferably from about 5 to 50weight percent, and units of formula (Ib) can comprise from about 99 to1 weight percent, preferably from about 95 to 50 weight percent. In onepreferred embodiment, the anionic polymer is a random, alternating orblock copolymer of units (Ia) and (Ib) wherein R₁ is hydroxyl, and eachof the remaining R groups is hydrogen, i.e., the polymer is a copolymerof ethylene and vinyl alcohol. In another preferred embodiment, theanionic polymer is a random, alternating or block copolymer of units(Ia) and (Ib) wherein R₁ is OC(O)R₅, where R₅ is methyl, and each of theremaining R groups is hydrogen, i.e., the polymer is a copolymer ofethylene and vinyl acetate.

In another embodiment, the anionic polymer is an anionic polymer havingneutralizable hydroxyl and/or dealkylable ether groups of formula (II):

wherein:

R₁-R₉ and R_(b) and R_(z) are as defined above;

R₁₀-R₁₂ are each independently selected from the group as defined abovefor R₂; and

R₁₃ is OH or OC(O)R₁₄, where R₁₄ is a lower alkyl; wherein x, y and zindicate relative weight percent of the different units. x can be fromabout 99 to 50 weight percent of the polymer, y can be from about 1 to50 weight percent of the polymer, and z ranges from about 0 to 50 weightpercent of the polymer. At least a portion of the neutralizable groupsR₁ are neutralized. When the amount of z is greater than zero, a portionof the groups R₁₀ can also be fully or partially neutralized, asdesired.

The anionic polymer compositions of the present invention can be used informing any golf ball components, i.e., in the cover, the center and/orone or more intermediate layer(s) and in any type of golf ball.Referring to FIG. 1, a golf ball 10 of the present invention cancomprise a core 12 and a cover 16 surrounding the core 12. Referring toFIG. 2, a golf ball 20 of the present invention can comprise a center22, a cover 26, and at least one intermediate layer 24 disposed betweenthe cover and the center. In one embodiment, the intermediate layer 24is an outer core layer, such that the core is formed from the center 22and the intermediate layer 24 and the ball has a single layer cover 26.In another embodiment, the intermediate layer 24 is an inner coverlayer, such that the cover is formed from the intermediate layer 24 andthe cover 26 and the ball has a single layer center 22. Each of thecover, the core, and the optional intermediate layer(s) may alsocomprise more than one layer, i.e., the golf ball can be a conventionalthree-piece wound ball, a two-piece ball, a ball having a multi-layercore and/or a mantle layer or layers, etc. Thus, referring to FIG. 3, agolf ball 30 of the present invention can comprise a core 32, a cover38, and intermediate layers 34 and 36 disposed between the cover and thecore. Although FIG. 3 shows only two intermediate layers, it will beappreciated that any number of core, intermediate, or cover layers maybe used, as desired.

The anionic polymer compositions can be used to form at least a portionof one or more layers of the golf ball, such as the cover or a portionof the cover, the core or a portion of the core, an intermediate ormantle layer or a portion thereof, etc. For example, the core of a golfball may contain at least one solid, hollow, or fluid portion, butpreferably the core contains at least one solid or fluid portion, andmore preferably the core contains a solid or fluid portion. The golfball may be prepared so that at least a portion of at least one of thecore, the at least one intermediate layer, and the cover is foamed,includes a density-modifying filler, or both.

In particular, two-piece golf balls 10 having a cover 16 surrounding acore 12 are within the scope of the invention, wherein the cover 16, thecore 12, or both the cover 16 and the core 12 comprise the anionicpolymer compositions described herein. Further, wound golf balls, inwhich a fluid, semi-solid, or solid or hollow core is surrounded by atensioned elastomeric material are also contemplated as being within thescope of the present invention. The fluid used in the core may be aliquid or a gas. Such anionic polymer components can also be used ingolf balls 20 or 30 having multiple cover, core, and/or intermediatelayers, and may be used in any one or more of such cover, core andintermediate layers. Preferably, at least the cover comprises an anionicpolymer composition of the present invention.

Blends of two or more anionic polymer compositions described above arealso included within the scope of the present invention.

Other polymers may also be used in golf balls according to the presentinvention, as conventionally used in any golf ball component, orcombined with the anionic polymer compositions of the present invention.Thus, the anionic polymer compositions of the present invention cancomprise compatible blends of at least one anionic polymer as describedabove and one or more additional polymers. Such blends can be formedusing blending methods well known in the art.

In particular, the anionic polymer blends can comprise compatible blendsof anionic polymers and ionomers, such as ethylene methacrylic acidionomers, and ethylene acrylic acid ionomers, and their terpolymers,sold commercially under the trade names SURLYN® and IOTEK® by DuPont andExxon respectively. The anionic polymer blends useful in the golf ballsof the invention can also include other polymers, such aspolyvinylalcohol, copolymers of ethylene and vinyl alcohol,poly(ethylethylene), poly(heptylethylene), poly(hexyldecylethylene),poly(isopentylethylene), poly(butyl acrylate), poly(2-ethylbutylacrylate), poly(heptyl acrylate), poly(2-methylbutyl acrylate),poly(3-methylbutyl acrylate), poly(N-octadecylacrylamide),poly(octadecyl methacrylate), poly(butoxyethylene),poly(methoxyethylene), poly(pentyloxyethylene),poly(1,1-dichioroethylene), poly(4-[(2-butoxyethoxy)methyl]styrene),poly[oxy(ethoxymethyl)ethylene], poly(oxyethylethylene),poly(oxytetramethylene), poly(oxytrimethylene), poly(silanes) andpoly(silazanes), polyamides, polycarbonates, polyesters, styrene blockcopolymers, polyetheramides, polyurethanes, main-chain heterocyclicpolymers and poly(furan tetracarboxylic acid diimides), as well as theclasses of polymers to which they belong.

The anionic polymer compositions of the present invention typically havea flexural modulus of from about 500 psi to 300,000 psi, preferably fromabout 2000 to 200,000 psi. The anionic polymer compositions typicallyhave a hardness of at least about 15 Shore A, preferably between about30 Shore A and 80 Shore D, more preferably between about 50 Shore A and60 Shore D. The loss tangent, or dissipation factor, is a ratio of theloss modulus over the dynamic shear storage modulus, and is typicallyless than about 1, preferably less than about 0.01, and more preferablyless than about 0.001 for the anionic polymer compositions measured atabout 23° C. The specific gravity is typically greater than about 0.7,preferably greater than about 1, for the anionic polymer compositions.The dynamic shear storage modulus, or storage modulus, of the anionicpolymer compositions at about 23° C. is typically at least about 10,000dyn/cm², preferably from about 10⁴-10¹⁰ dyn/cm², more preferably fromabout 10⁶ to 10¹⁰ dyn/cm².

When the anionic polymer compositions are combined with an additionalpolymer component, the additional polymer component is present in anamount of about 1 to 99 percent by weight, preferably about 5 to 80percent by weight, based on the total weight of the anionic polymer andthe additional polymer.

Further compositions may also be added to the anionic polymer componentsof the invention, such as, for example, coloring agents, reactionenhancers, crosslinking agents, blowing agents, dyes, lubricants,fillers (including density modifying fillers), excipients, process aidsand other compounds commonly added to polymeric materials and/or golfball compositions.

The composition of any golf ball component that does not contain theanionic polymer compositions disclosed herein can be any suchcomposition known to those of ordinary skill in the art. Suchcompositions may be readily selected by those of ordinary skill in theart, for example, from one of the many U.S. Patents assigned to AcushnetCompany. The resultant golf balls typically have a coefficient ofrestitution of greater than about 0.7, preferably greater than about0.75, and more preferably greater than about 0.78. The golf balls alsotypically have a compression of at least about 40, preferably from about50 to 120, and more preferably from about 60 to 100. As used herein, theterm “compression” means as measured by an ATTI Compression Gauge. Thesegauges are well known to those of ordinary skill in the art and arecommercially available from Atti Engineering Corp. of Union City, N.J.

The present invention relates to golf balls of any size. While USGAspecifications limit the size of a competition golf ball to more than1.68 inches in diameter, golf balls of any size can be used for leisuregolf play. The preferred diameter of the golf balls is from about 1.68inches to about 1.8 inches. The more preferred diameter is from about1.68 inches to about 1.76 inches. A diameter of from about 1.68 inchesto about 1.74 inches is most preferred. The cover of the golf ballstypically has a thickness of at least about 0.03 inches, preferably 0.03to 0.125 inches, and more preferably from about 0.05 to 0.1 inches. Thegolf balls also typically have at least about 60 percent dimplecoverage, preferably at least about 70 percent dimple coverage, of thesurface area.

Anionic polymer layers may be produced in golf balls in accordance withthe present invention by various techniques which are known in the art,such as by injection molding or compression molding a layer of anionicpolymer material about a previously formed center or core, cover, orintermediate layer. Cores comprising an anionic polymer composition mayalso be formed directly by injection molding or compression molding.When the layer or core is injection molded, a physical or chemicalblowing or foaming agent may be included to produce a foamed layer, ifdesired. Blowing or foaming agents useful in forming foamed anionicpolymer blends may be readily selected by one of ordinary skill in theart.

In a further embodiment, foamed anionic polymer blends may be formed byblending ceramic or glass microspheres with the anionic polymer eitherduring or before the molding process. Polymeric, ceramic, metal, andglass microspheres are useful in the invention, and may be solid orhollow and filled or unfilled. Microspheres up to about 1000 micrometersin diameter are useful in the anionic polymer compositions of theinvention.

For compression molded layers, half-shells made by injection molding ananionic polymer composition in a conventional half-shell mold or bycompression molding commercially available sheets of anionic polymercompositions are used. The half-shells are placed about a previouslyformed center or core, cover, or mantle layer, and the assembly isintroduced into a compression molding machine, and compression molded atabout 250° F. to 400° F. The molded balls are then cooled while still inthe mold, and finally removed when the layer is hard enough to behandled without deforming. Additional core, intermediate, and coverlayers are then molded onto the previously molded layers, as needed,until a complete ball is formed.

After the final cover layer of the ball has been molded, the ballundergoes various conventional finishing operations such as buffing,painting and stamping, all of which are well known in the art.

Blending of the anionic polymer compositions and the optional additionalpolymers is accomplished in a conventional manner using conventionalequipment. For example, a conventional injection molding machine may beused either to make preformed half-shells for compression molding or formolding flowable anionic polymer compositions using a retractable-pinmold.

The invention described and claimed herein is not to be limited in scopeby the specific embodiments herein disclosed, since these embodimentsare intended as illustrations of several aspects of the invention. Anyequivalent embodiments are intended to be within the scope of thisinvention. Indeed, various modifications of the invention in addition tothose shown and described herein will become apparent to those skilledin the art from the foregoing description. Such modifications are alsointended to fall within the scope of the appended claims.

What is claimed is:
 1. A golf ball comprising center and a coverdisposed thereon, wherein at least a portion of the center comprises ananionic polymer comprising repeat units of formula Ia:

wherein R₁ is OH, OC(O)R₅, O⁻M^(+V), (CH₂)_(n)R_(b), (CHR_(z))_(n)R_(b),or aryl, wherein n is at least 1, R₅ is a lower alkyl, M is a metal ion,V is an integer from 1 to 5, R_(b) is OH, OC(O)R₅, O⁻M^(+V) and R₂ is alower alkyl or aryl, R₂, R₃ and R₄ are each independently selected fromthe group consisting of hydrogen, straight-chain or branched-chain loweralkyl, and substituted alkyl in which one or more hydrogen atoms isreplaced by a substituent selected from the group consisting of COOH,SO₃H, NH₂, or a lower alkyl substituted or di-substituted amine,halogen, OH, SH, silicone, and lower alkyl ether.
 2. The golf ball ofclaim 1, wherein the anionic polymer further comprises at least one unitof formula Ib:

wherein R₆, R₇, R₈ and R₉ are each independently selected from the groupconsisting of hydrogen, straight-chain or branched-chain lower alkyl,and substituted alkyl, in which one or more hydrogen atoms is replacedby a substituent selected from the group consisting of COOH, SO₃H, NH₂or a lower alkyl substituted or di-substituted amine, halogen, OH, SH,silicone, and lower alkyl ether.
 3. The golf ball of claim 2, whereinthe anionic polymer is a random, alternating or block copolymer of theunits of formula Ia and formula Ib, wherein R₁ is OH or OC(O)R₅, andwherein R₂, R₃, R₄, R₆, R₇, and R₉ are hydrogen.
 4. The golf ball ofclaim 2, wherein the units of formula Ia comprise from about 5 to 50weight percent of the anionic polymer and the units of formula Ibcomprise from about 95 to 5 weight percent of the anionic polymer. 5.The golf ball of claim 1, wherein the metal ion is selected from thegroup consisting of lithium, sodium, potassium, zinc, magnesium,titanium, tungsten, or calcium.
 6. The golf ball of claim 1, furthercomprising at least one intermediate layer disposed between the centerand the cover.
 7. The golf ball of claim 6, wherein the intermediatelayer comprises a tensioned elastomeric material.
 8. The golf ball ofclaim 6, wherein the at least one intermediate layer comprises ananionic polymer having at least one neutralizable hydroxyl,deacetylable, or dealkylable ether group, wherein at least a portion ofthe neutralizable hydroxyl, deacetylable, or dealkylable ether group areneutralized, deacetylated, or dealkylated with a metal ion.
 9. The golfball of claim 1, wherein the cover comprises at least two layers andwherein at least one layer of the cover comprises the anionic polymer.10. The golf ball of claim 1, wherein the cover has a thickness of about0.03 inches to 0.125 inches.
 11. The golf ball of claim 1, wherein theanionic polymer has at least one of a flexural modulus from about 500psi to about 300,000 psi, a hardness of about 15 Shore A or greater, aspecific gravity of about 0.7 or greater, a dynamic shear modulus ofabout 10⁴ dyn/cm² or greater, or a loss tangent of about 1 or less. 12.The golf ball of claim 6, at least one of the center, the at least oneintermediate layer, or the cover is foamed, comprises adensity-modifying filler, or both.
 13. The golf ball of claim 1, furthercomprising at least one additional polymer selected from the groupconsisting of ionomers, polyvinylalcohol, copolymers of ethylene andvinyl alcohol, poly(ethylethylene), poly(heptylethylene),poly(hexyldecylethylene), poly(isopentylethylene), poly(butyl acrylate),poly(2-ethylbutyl acrylate), poly(heptyl acrylate), poly(2-methylbutylacrylate), poly(3-methylbutyl acrylate), poly(N-octadecylacrylamide),poly(octadecyl methacrylate), poly(butoxyethylene),poly(methoxyethylene), poly(pentyloxyethylene),poly(1,1-dichloroethylene), poly(4-[(2-butoxyethoxy)methyl]styrene),poly[oxy(ethoxymethyl)ethylene], poly(oxyethylethylene),poly(oxytetramethylene), poly(oxytrimethylene), poly(silanes) andpoly(silazanes), polyamides, polycarbonates, polyesters, styrene blockcopolymers, polyetheramides, polyurethanes, main-chain heterocyclicpolymers, poly(furan tetracarboxylic acid diimides), and mixturesthereof.
 14. The golf ball of claim 1, wherein the center comprises acore and an intermediate layer.
 15. The golf ball of claim 6, whereinthe intermediate layer is formed of the anionic polymer.
 16. A golf ballcomprising a core, a cover disposed concentrically about the core, andat least one intermediate layer disposed between the core and the cover,wherein the cover comprises a first cover layer and a second coverlayer, and wherein at least one of the core or the at least oneintermediate layer is formed of a composition comprising an anionicpolymer comprising repeat units of formula Ia:

wherein R₁ is OH, OC(O)R₅, O⁻M^(+V), (CH₂)_(n)R_(b), (CHR₂)_(n)R_(b) oraryl, wherein n is at least 1, R₅ is a lower alkyl, M is a metal ion, Vis an integer from 1 to 5, R_(b), is OH, OC(O)R₅, O⁻M^(+V), and R_(Z) isa lower alkyl or aryl, R₂, R₃ and R₄ are each independently selectedfrom the group consisting of hydrogen, straight-chain or branched-chainlower alkyl, and substituted alkyl in which one or more hydrogen atomsis replaced by a substitutent selected from the group consisting ofCOOH, SO₃, NH₂, or a lower alkyl substituted or di-substituted amine,halogen, OH, SH, silicone, and lower alkyl ether.
 17. The golf ball ofclaim 16, wherein the anionic polymer further comprises units of formulaIb:

wherein R₆, R₇, R₈ and R₉ are each independently selected from the groupconsisting of hydrogen, straight-chain or branched-chain lower alkyl,and substituted alkyl, in which one or more hydrogen atoms is replacedby a substituent selected from the group consisting of COOH, SO₃, NH₂ ora lower alkyl substituted or di-substituted amine, halogen, OH, SH,silicone, and lower alkyl ether.
 18. The golf ball of claim 16, whereinthe at least one intermediate layer comprises a tensioned elastomericmaterial.
 19. The golf ball of claim 16, wherein the first cover layeris formed of a composition comprising an anionic polymer having at leastone neutralizable hydroxyl, deacetylable, or dealkylable ether group,wherein at least a portion of the neutralizable hydroxyl, deacetylable,or dealkylable ether group are neutralized, deacetylated, or dealkylatedwith a metal ion.
 20. The golf ball of claim 16, wherein the first coverlayer and the second layer each have a thickness from about 0.03 inchesto about 0.125 inches.
 21. The golf ball of claim 16, wherein the corecomprises at least two layers and wherein at least a portion of the coreis formed of the composition.
 22. The golf ball of claim 16, wherein theanionic polymer has at least one of a flexural modulus from about 500psi to about 300,000 psi, a hardness of about 15 Shore A or greater, aspecific gravity of about 0.7 or greater, a dynamic shear modulus isabout 10⁴ dyn/cm² or greater, a loss tangent of about 1 or less, or acombination thereof.
 23. The golf ball of claim 16, further comprisingat least one additional polymer present in an amount from about 1 weightpercent to about 99 weight percent of the composition.
 24. The golf ballof claim 23, wherein the at least one additional polymer is present inan amount from about 5 weight percent to about 80 weight percent of thecomposition.
 25. The golf ball of claim 23, wherein the at least oneadditional polymer is selected from the group consisting of ionomers,polyvinylalcohol, copolymers of ethylene and vinyl alcohol,poly(ethylethylene), poly(heptylethylene), poly(hexyldecylethylene),poly(isopentylethylene), poly(butyl acrylate), poly(2-ethylbutylacrylate), poly(heptyl acrylate), poly(2-methylbutyl acrylate),poly(3-methylbutyl acrylate), poly(N-octadecylacrylamide),poly(octadecyl methacrylate), poly(butoxyethylene),poly(methoxyethylene), poly(pentyloxyethylene),poly(1,1-dichloroethylene), poly(4-[(2-butoxyethoxy)methyl]styrene),poly[oxy(ethoxymethyl)ethylene], poly(oxyethylethylene),poly(oxytetramethylene), poly(oxytrimethylene), poly(silanes) andpoly(silazanes), polyamides, polycarbonates, polyesters, styrene blockcopolymers, polyetheramides, polyurethanes, main-chain heterocyclicpolymers, poly(furan tetracarboxylic acid diimides), and mixturesthereof.
 26. The golf ball of claim 16, further comprising coloringagents, reaction enhancers, crosslinking agents, blowing agents, dyes,lubricants, fillers, excipients, process aids, or mixtures thereof. 27.A golf ball comprising a core, at least one intermediate layer disposedabout the core, and a cover having an inner cover layer and an outercover layer disposed concentrically about the intermediate layer,wherein at least one of the inner cover layer or outer cover layer andat least one of the core or the at least one intermediate layer areformed of a composition which comprises an anionic polymer comprisingunits of formula (II):

wherein: R₁ is OH, OC(O)R₅, O⁻M^(+V), or substituted or unsubstituted(CH₂)_(n)R_(b), (CHR_(Z))_(n)R_(b), or aryl, wherein n is at least 1, R₅is a lower alkyl, M is a metal ion, V is an integer from 1 to 5, R_(b)is OH, OC(O)R₅, O⁻M^(+V), and R_(Z) is a lower alkyl or aryl; R₂-R₁₂ areeach independently selected from the group consisting of hydrogen,straight-chain or branched-chain lower alkyl, and substituted alkyl, inwhich one or more hydrogen atoms is replaced by a substituent selectedfrom the group consisting of COOH, SO₃H, NH₂ or a lower alkylsubstituted or di-substituted amine, halogen, OH, SH, silicone, andlower alkyl ether; R₁₃ is OH or OC(0)R₁₄, where R₁₄ is a lower alkyl; xranges from about 99 to 50 weight percent of the polymer, y ranges fromabout 1 to 50 weight percent of the polymer, and z ranges from about 0to 50 weight percent of the polymer, and wherein the anionic polymer hasa flexural modulus from about 500 psi to about 300,000 psi, a hardnessof at least about 15 Shore A, a specific gravity of at least about 0.7,a dynamic shear storage modulus of at least about 10⁴ dyn/cm⁴ at about23° C., a loss tangent of less than about 0.01 at about 23° C.
 28. Thegolf ball of claim 27, wherein R₁ is OH or OC(O)R₅, and wherein R₂, R₃,R₄, R₆, R₇, R₈, and R₉ are hydrogen.
 29. The golf ball of claim 27,wherein the outer cover layer and the intermediate layer are formed ofthe composition.
 30. The golf ball of claim 27, wherein the intermediatelayer comprises a tensioned elastomeric material.
 31. The golf ball ofclaim 27, wherein at least one of the core, the at least oneintermediate layer, the inner cover layer, or the outer cover layer isfoamed, comprises a density-modifying filler, or both.
 32. The golf ballof claim 27, wherein the outer cover layer has a thickness of about 0.03inches to 0.125 inches.
 33. The golf ball of claim 27, wherein the corecomprises at least two layers.
 34. The golf ball of claim 27, whereinthe anionic polymer has a flexural modulus from about 2000 psi to about200,000 psi, a hardness from about 30 Shore A to about 80 Shore D), aspecific gravity of about 1 or greater, a dynamic shear storage modulusfrom about 10⁶ dyn/cm² to about 10¹⁰ dyn/cm² at about 23° C., a lesstangent of less than about 0.01 at about 23° C.
 35. The golf ball ofclaim 27, further comprising at least one additional polymer selectedfrom the group consisting of ionomers, polyvinylalcohol, copolymers ofethylene and vinyl alcohol, poly(ethylethylene), poly(heptylethylene),poly(hexyldecylethylene), poly(isopentylethylene), poly(butyl acrylate),poly(2-ethylbutyl acrylate), poly(heptyl acrylate), poly(2-methylbutylacrylate), poly(3-methylbutyl acrylate), poly(N-octadecylacrylamide),poly(octadecyl methacrylate), poly(butoxyethylene),poly(methoxyethylene), poly(pentyloxyethylene),poly(1,1-dichloroethylene), poly(4-[(2-butoxyethoxy)methyl]styrene),poly[oxy(ethoxymethyl)ethylene], poly(oxyethylethylene),poly(oxytetramethylene), poly(oxytrimethylene), poly(silanes) andpoly(silazanes), polyamides, polycarbonates, polyesters, styrene blockcopolymers, polyetheramides, polyurethanes, main-chain heterocyclicpolymers, poly(furan tetracarboxylic acid diimides), and mixturesthereof.